492 
W. L. WILLIAMS. 
sions and that of a comatose cow should correspond, and by 
this mode of reasoning attempts to prove the non-identity of 
the two affections under consideration. Dr. Butler should, 
we think, bear in mind that body temperature depends largely 
upon two factors, the amount of heat generated within the 
body by means of tissue change, and the facility for the elimi¬ 
nation of this heat when once formed. 
That the nervous system exerts a far-reaching influence 
over both these processes has been fully demonstrated by 
physiological experiment. In sleep (brain anaemia) we have a 
distinct depression of body temperature, and the same holds 
true in almost, if not all cases accompanied by coma. Evidently 
the lower temperature in coma must be referred to a suspen¬ 
sion of the thermogenic functions of the nervous system, not 
alone in sleep, nor in hibernation, but more markedly in coma 
preceding death in freezing or from certain drugs (curare, alco¬ 
hol), producing probably analogous states of the nervous 
system. In no disease or pathological slate perhaps, have we 
a better example of this law than in parturient apoplexy of 
cows, and in it we see a highly economic provision of nature. 
It is estimated, and upon good grounds, that in most animals 
a large proportion of animal heat is given off by the skin, and 
clinical observation goes far to show that in disease in which, 
owing to exalted tissue change, there is an excessive produc¬ 
tion of heat, the skin plays if anything a more important role 
in the maintenance of the normal body temperature than in 
health. On an excessively hot day, so long as a man or a 
horse sweats freely all goes well, but once this ceases, sun¬ 
stroke is the result. In both cases the skin ceases to perform 
its normal action and animal heat accumulates. 
In man coma supervenes rapidly as a rule, while in the 
horse, tetanus and delirium set in with equal promptness and 
frequency, and the result is a comparatively higher fatality in 
horse than in man, because probably with coma the produc¬ 
tion of heat largely ceases in the latter, while in the tetanus 
and delirium of the horse the thermogenic functions continue. 
Again, in that disease which I ventured to describe as 
